The development of a blood substitute, while of primary concern to the Dept. of Defense for Combat Victims, has important implications for the civilian population since it can be sterilized and rendered virus free. Scale up to 50 l/run is being started at the Div. of Blood Resources, Letterman Army Inst. of Research under Col. Robert Winslow. The development of various instruments, for the biophysical study of hemoglobin begun in this section many years ago, are now in demand at NIH, LAIR, and various univ. labs. The oxygen equilibrium curve analyses we have been developing with the considerable assistance of Horace Cascio, BEIB Elec. Eng., and the Fabrication Section of BEIB, has been finished and is presently being debugged. Utilizing summer personnel, we plan to thoroughly test it on HbAo furnished by LAIR. Effects of temperature and chloride binding to hemoglobin on the equilibrium curve will be studied both manometrically and spectrometrically to establish a standard curve. A calorimetric determination of the heats of binding will be done with C. Mudd, BEIB Applied Clinical Engineering. New advances in Near InfraRed Spectroscopy have led to the development of a system for identifying ATP, ADP, and P04= in a mixture with a buffer, such as Bis-Tris, and salts such as KCl. Preliminary work has permitted us to identify two lines for each compound when done singly, with 99% correlation. The next step is to attempt to have as high a correlation in mixtures. The present spectrometer permits scanning any octave, i.e. 600 to 1200, 900 to 1800, 1200 to 2400 nm in 200 msec. For the above work, 50 scans were used. We would be limited to a time resolution of 10 sec. For kinetics studies 10 msec. or better is required. We are presently exploring utilizing lasing diodes for such work. These have 10(5th) greater light intensity and a time resolution of nanoseconds.